The present inventions relate generally to satellite positioning system receivers, and more particularly to locating satellite positioning system enabled mobile wireless communications handsets.
U.S. Pat. No. 5,225,842 entitled xe2x80x9cVehicle Tracking System Employing Global Positioning System (GPS) Satellitesxe2x80x9d discloses a vehicle tracking system comprising a master station that computes and displays the position of a large number of vehicles using GPS sensor data transmitted from the vehicles at low data rates. The master station also computes an aided navigation solution for vehicles that report sensor data from less than four satellites by estimating altitude from a digital map.
U.S. Pat. No. 5,646,857 entitled xe2x80x9cUse of An Altitude Sensor to Augment Availability of GPS Location Fixesxe2x80x9d discloses integrating elevation readings from an altimeter or barometer with global positioning system (GPS) determined elevation coordinates at the same location as the altimeter or barometer reading.
U.S. Pat. No. 6,061,018 entitled xe2x80x9cMethod And System For Using Altitude Information In A Satellite Positioning Systemxe2x80x9d discloses a mobile satellite positioning system (SPS) receiver that transmits satellite pseudo-range data to GPS location server, which computes the position of the SPS receiver using altitude aiding information. The GPS location server estimates the altitude of the receiver based upon the altitude of the cell site in which the receiver is located, for example the approximate altitude of the cell site transmitter or a mathematical representation of the altitude in the geographical vicinity of the transmitter.
The various aspects, features and advantages of the present invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description of the Invention with the accompanying drawings described below.